U-Pb ages of individual detrital zircon grains from deltaic and turbidite sandstones of the lower to middle Pennsylvanian Haymond Formation (Marathon basin, west Texas) range from 320 Ma to 3 Ga, indicating a mixed provenance broadly similar to that of Ouachita Carboniferous turbidites and related fluvio-deltaic facies of Arkansas-Oklahoma. Differences with the Ouachita assemblage are attributed to the unique depositional setting of the Haymond Formation, which records final closure of a Hercynian-age remnant ocean basin at the western termination of the Ouachita-Marathon suture zone. Tectonic and sedimentary recycling along subduction zones separating Gondwanan (upper plate) and Laurentian (lower plate) blocks likely contributed to the Laurentia-dominated distribution of age provinces observed in the zircon population. Detrital-zircon age spectra are nearly identical for both facies of the Haymond Formation, reinforcing the hypothesis that subaerial fan or braid delta sandstones, and foredelta submarine-ramp turbidites, were part of an integrated depositional system fed by the same sources.
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